Preform for a curved composite stiffener for an axisymmetric part such as a collar

A preform for a curved composite stiffener for an axisymmetric part comprising at least one web and at least one flange curved about an axis of revolution of said preform and defining at least one of a “T” and an “I” shaped section, wherein:

• the at least one web comprises a plurality of warp yarns circumferentially oriented relative to the axis of revolution of the preform to define web warp yarn layers, and a plurality of weft yarns oriented radially relative to said axis of revolution, wherein the weft yarns are inserted between the warp yarns so as to define a binding zone of the warp yarn layers to each other by the weft yarns;
• and
• the at least one flange comprises a plurality of warp yarns circumferentially oriented relative to the axis of revolution of the preform to define flange warp yarn layers, and a plurality of weft yarns parallel to said axis of revolution to define an unbinding zone in which the flange warp yarn layers are not bound by the weft yarns.